激光熔覆Ti基WC增强复合涂层的裂纹研究
Research on Cracks of Ti-based WC Reinforced Composite Coating by Laser Cladding
匡建新1, 汪新衡1, 秦小平1, 朱航生2
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作者单位：(1. 湖南工学院 机械工程系, 湖南 衡阳 421002; 2. 衡阳丰顺车桥有限公司 产品部, 湖南 衡阳 421002)
中文关键字：激光熔覆； 裂纹； Ti基合金； WC金属陶瓷； 热膨胀系数
英文关键字：laser cladding; cracks; Ti-based alloy; WC metal-ceramic; thermal expansion coefficient
中文摘要：研究了激光熔覆Ti基WC增强复合涂层的开裂行为。结果表明：涂层裂纹主要有熔覆层内的弥散穿晶裂纹，源于激光熔覆层边缘的粗大沿晶裂纹，WC颗粒上的扩展裂纹。开裂是由于熔覆层与金属基体两种材料之间极高的温度梯度，以及它们的熔点、热膨胀系数、弹性模量及导热系数等物理性能参数的差异很大所致。同时开裂倾向还受激光工艺参数、涂层合金粉的配比以及强化相的形状、大小等因素的影响。
英文摘要：The cracking behavior of Ti-based WC reinforced composite coating by laser cladding was studied. The results show that the cracks of composites are mainly dispersed with diffuse transgranular cracks in the cladding layer, thick intergranular cracks from the edge of laser cladding layer of coarse and extended cracks on WC particles. The cracking is due to physical performance parameters such as the extreme high temperature gradient, different melting, thermal expansion coefficients, modulus and thermal conductivity between the matrix and the coating. At the same time, the cracking trend is affected by the laser cladding process parameters, the alloy powders content, and the shape and size of the reinforced phases.